Valve for rock-drilling machines.



No. 784,320. PATENTED MAR. 7, 1905. J. E. H. GROSE.

VALVE FOR ROCK DRILLING MACHINES.

APPLIOATION FILED SEPT. e. 1904'.

an y u x 1 I! 1 F I i UNITED STATES Patented March '7, 1905.

PATENT OFFICE.

VALVE FOR ROCK-DRILLING MACHINES.

SPECIFICATION forming part of Letters Patent No. 784,320, dated March 7, 1905.

Application filed September 6, 1904. Serial No. 223,433-

To rtL/i whom it may concern:

Be it known that I, JAMEs EDWARD HOSKINS Gnosu, a subject of the King of England, residing at (arermiston, in the Colony of the Transvaal, have invented certain new and useful improvements in Valves for Rock-Drilling Machines or Engines, of which the following is a specification.

This invention relates to rock-drilling machines or engines operated by means of compressed air or other elastic motive fluid.

The invention is designed. first, to obviate the impact of the piston on the back stroke if from any cause the valve is not quickly reversed; secondly, to obtain a more positive action of the valve by means of a constant leakage of the motive fluid alternately to either end of the valve; thirdly, to provide a central inlet for the motive fluid, whereby an equal pressure is obtained on both sides of the valve, and consequently an equal wearing of the valve; fourthly, to control the exhaust from the back end of the cylinder by means of both the piston and valve, the valve operating to control the exhaust on the forward stroke and the piston on the return stroke, and, fifthly, to enable the machine to be run with a very short stroke, if desi1'ed--as, for example, in the starting of holes.

In a machine or engine constructed in accordance with the invention on the forward stroke the exhaust from the rear end of the cylinder occurs only when the valve changes to admit the motive fluid to the front of the piston after the impact of the drilling-bit. On the rearward stroke the exhaust is cut ofi by the piston independently of the valve after it has traversed a portion of its stroke, thereby bottling up a quantity of the fluid, which is compressed during the remainder of the rearward stroke at the back end of the cylinder and arrests the movement of the piston before the back end is reached. In addition to economizing the motive fluid this prevents the piston striking the back end should the valve become sluggish in its movement, owing to grit or other substances entering the inlet or from any other cause. In the valve the first space or port from each end of the valve being used for the exhaust only, (the motive fluid passing in through a central port or space,) the action of the valve is not affected by wear owing to excessive leakage passing through to the end. The valve is subjected to an equal pressure on all sides, so that wear will only take place by the friction caused by its own weight.

The invention will now be described in detail by the aid of the accompanying drawings, wherein- Figure 1 represents a longitudinal section of the machine; Fig. 2, a plan of the machine with the valve and valve-chest removed; Fig. 3, a section on line a: m, Fig. 1; Fig. 4, a section on line ;1 9 Fig. 1; Fig. 5, a section on line .2 Fig. 1; Fig. 6, a section on line :r ;1 Fig. 1; and Fig. '7, a section of a part of the machine on line :0 .2, Fig. 1.

The machine comprises the cylinder A, in which is arranged the piston B, turned down or reduced in diameter at the center to form the annular recess 5 between the pistons 6 6 C is the front head, through which the piston-rod D works. The forward extremity of the piston-rod 1) has attached to it in any convenient manner the drill-bit or other boring tool to which the percussive reciprocating motion is to be imparted.

The cylinder A, as shown at a, is constructed in the ordinary or any other convenient manner to be mounted in a cradle or carriage, in which it is moved in a forward or rearward direction by means of the feedingscrew usually employed in this class of machine. The cyliner A is also constructed, as shown at a, to carry the feed-nut through which the feed-screw works to traverse the cylinder A forward in its cradle or carriageas the boring proceeds.

E is a ring which serves for carrying the rifled-bar and ratchet mechanism, which may be of any convenient construction for transmitting the intermittent rotary motion to the piston, piston-rod, and drilling bit or tool on the back stroke.

F designates the valve box or chest, arranged on the cylinder A. The cylinder A is formed with bosses or projections (0 in which are tapped holes a and the valve box or chest F is constructed with coincident lugs or projections a and holes (i coinciding with the.

holes a in the cylinder A, (see Fig. 5,) in which are arranged screw-bolts for fixing the valve box or chest F in position on the cylinder.

The ends of the valve box or chest F are closed by the caps or covers f, (see Fig. 1,) which caps or covers are secured in position by longitudinal bolts arranged in the boltholes f 1 designates the main inlet-port, through which the motive fluid is admitted to the machine, and 2 and 3 are the ports leading to either end of the cylinder A, which are alternately placed in communication with the main inlet-port 1 by means of the valve 4. The valve 4 is constructed with the four pistons 5, 6, 7, and 8. The two end pistons 5 and 8 serve for reversing the valve to alternately admit the motive fluid along the ports 2 3.

9, 10, 11, 12, 13, and 14 are the ports constructed in the valve-chest F, which ports are controlled by the four pistons 5, 6, 7, and 8. The port 11 is in communication with the main inlet-port 1. The ports 9 and 13, which are the exhaust-ports, communicate with'a common exhaust-port 15. The ports 10 and 12, which are controlled by the pistons 6 and 7, serve for alternately placing the ports 2 and 3 in communication with the'main inlet 1. The piston 6 serves for placing the port 2 in communication with the exhaust through the port 9, and piston 7 serves for placing the port 13 in communication with the back end of the cylinder, through the holes 16 and port 17, to place the back end of the cylinder in communication with the exhaust.

.In the cylinder Athree (more or less) holes 18 are formed, which place the interior of the cylinder between the pistons b b in communication with the exhaust-port 15, so that the interior of the cylinder between the pistons is always in communication with exhaust.

19 is a port communicating at one end with the interior of the cylinder A and with a groove 20, which may be formed in the face of the cylinder A, as shown, or in the face of the valve-chest F. The groove 20 is placed in communication with the main inlet l-by the port 20, as seen in Fig. 2.

21 is a port formed in the valve-chest F, placing the groove 20 in communication with the valve-chest F at the rear of the piston 5.

22 is a port (see Figs. 2, 4, and 7) communicating with the interior of the cylinder A at one end and with a groove 23, which may be formed in the face of the cylinder A, as shown, or in the face of the valve chest F. The groove 23 is placed in communication with the main inlet 1 by means of the port 23 24 is a port formed in the valve-chest F, placing the groove 23 in communication with the valve-chest F at the rear of the piston 8.

The several parts are shown in the positions they assume when the drill-bit has impinged upon the rock. The valve 4 has been reversed, and the motive fluid is passing to the front end of the cylinder A to move the piston B on its rearward and idle stroke. In this position the piston 6 is closing the port 9, and consequently the port 2, to exhaust, and the main inlet 1 is open through the ports 11 and 10 of the supply-port 2. time the air passing up the port 20, along the groove 20 and port 19, into the cylinder A is free to escape from the interior of the latter through one or other of the ports 18. The air in the cylinder A at the rear of the piston B is free to escape through the holes 16 and ports 17, 14, and 13 to the exhaust 15. The valve 4 is maintained in this position by the air passing from the main inlet 1, along the port 23*, groove 23, port 24, to the rear of the piston 8 of the valve, the port 22 being at this time closed to the interior of the cylinder A by the piston b of the piston B.

As the piston B moves through its rearward stroke it closes ports 16, so that the air contained within the cylinder A is bottled up and utilized as a cushion for the piston B on the back stroke. The port 19 is closed, closing the groove 20 to the exhaust 15, whereupon the air at the initial pressure passing along the port 20 to the groove 20 from the main inlet 1 passes along the port 21 to the end of the piston 5 of the valve 4, and the port 22 being open to the center of the piston B and to exhaust the reversal of the valve 4 is thereby eflected. This cycle of operations is reversed on the forward movement of the piston.

WVhat I claim as my invention, and desire to protect by Letters Patent, is

1. In a rock-drilling machine or engine, in combination, the cylinder A and piston B arranged therein, the valve-chest F on the cylinder formed with the ports 9, 10, 11, 12, 13 and 14, the valve 4 arranged in the valvechest Fformed with the pistons 5, 6, 7 and 8, the cylinder being formed with a port 17 and the holes 16 placing said port 17 in communication with the interior of the cylinder said port 17 communicating with the port 14 in the valve-chest, the port 22, groove 23, ports 24 and 23 placing the interior of the cylinder and the main supply-port 1 in communication with the end of the valve-chest, the ports 18 placing the center portion of the cylinder in communication with the exhaust-port 15, the ports 19, 20. 20? and 21 placing the interior of the cylinder and the main supplyport in communication with the other end of the valve-chest, the ports 19 and 22 being controlled by the piston to alternately close said ports to the exhaust 15 to effect the reversal of the valve4, substantially as described.

2. In a rock-drilling machine or engine, in combination, the cylinder A constructed with the main inlet 1, the ports 2 and 3 placing At the same nication with either end of the cylinder, the

ISO

port 17, holes 16 placing the rear end of the cylinder in communication with said port 17, said port 17 communicating with one end of the valve-chest F, the ports 18 placing the center portion of the cylinder between the two parts of the piston in communication with the exhaust 15, the exhaust-port 15, the ports 22, groove or port 23, and ports 23 and 24 placing the cylinder in communication with the main supply-port and with one end of the valve-chest, said port 22 being controlled by the piston to close said port 22 to exhaust to reverse the valve, the port 19, groove or port 22, ports 20 and 21 placing the cylinder in communication with the main supply-port 1 and with the other end of the valve-chest, said port 19 being controlled by the piston to close said port 19 to exhaust to reverse the valve,

the valve with the exhaust 15 through the port 13, substantially as described.

In witness whereof I have hereunto set my hand in the presence of two subscribing witnesses.

JAMES EDWARD HOSKINS GROSE.

Witnesses:

CHAs. OVENDALE, R. OVENDALE. 

